1. Field of the Invention
The present invention relates to a conductive film for a flat Braun tube and a solution for preparing such a film, and more particularly to solution for preparing a conductive film which can eliminate electrons remaining on a fluorescent screen and secondary electrons when object images are displayed on a flat Braun tube.
2. Description of the Prior Art
Generally, a flat Braun tube has a construction as illustrated in FIG. 1, wherein electrons generated from an electron gun 1 are concentrated and accelerated at a grid, deflection yoke 2 and the like to thereby be emitted directly onto a fluorescent screen 3.
At this moment, visible rays emitted from the fluorescent screen 3 are reflected onto an aluminum film interposed between the fluorescent screen 3 and a screen panel 4 to thereby form pictorial images.
Some of the electrons irradiated to the fluorescent screen 3 stay at the screen 3, and when those electrons collides with the screen 3, secondary electrons are generated out of the collision to thereby make the screen 3 unable to form subsequent images.
Accordingly, as a means of eliminating the residual electrons and secondary electrons, a conductive film should be installed between the screen 3 and an inner graphite element formed on an inner panel 6.
As the conductive film, a graphite film, an indium oxide (In2,O3) thin film, an indium oxide-tin oxide (ITO) thin film, a tin oxide thin film, a tin oxide-antimonial oxide thin film (SnO2-Sb2O3) and the like are utilized.
However, in case of using graphite film for the conductive layer, there is a drawback of poor appearance, resulting in general usage of the indium oxide-tin oxide thin film (ITO), tin oxide-antimonial oxide thin film and the like.
As conventional methods for forming the conductive layer, a sputtering method, E-Beam method and the like have been utilized. However, these methods and materials thereof cost a great deal of money, making it difficult to apply the same to a flat Braun tube.
For example, a spray method utilizing a thermal decomposition technique described on pages 618-622, the 7th issue of volume 47 of "Applied Physics" published by the electronic development department of Shibaura laboratory situated in 3-9-14, Shibaura, Minatoku, Tokyo 108, Japan, has been used to solve the aforementioned drawbacks. However that method calls for heating of the material to be used for formation of transparent conductive film to over 400.degree. C. and spraying of a InCl3/SnCl4 solution for a sufficient conductivity characteristics.
If the aforementioned method is applied to a flat Braun tube, there arise various problems ranging from degradation of fluorescent material, to manufacturing difficulty, to deterioration in operational efficiency, and the like.
Accordingly, it is an object of the present invention to provide a solution for manufacturing conductive film for a low-priced flat Braun tube, which can improve the conductivity and operational efficiency of the tube.